PROBLEM: Reproducing the benefits of the delay phenomenon without the risks and cost of a surgical procedure has long been a goal of skin flap physiologists. After the success of the suture-delay technique and argon tunable dye laser in improving survival in McFarlane skin flaps, important questions remained: (1) will laser delay be effective in dermal flaps, (2) can induction of collateral blood flow be documented, and (3) is the KTP laser, which is generally more available to otolaryngologists, more effective than the argon tunable dye laser. METHODS: The KTP and argon tunable dye lasers were compared by use of the laser-delay technique, with two outcome measures-blood flow and survival. The laser-delay procedure was accomplished with the laser in a noncutting mode in an attempt to coagulate cutaneous vessels at the periphery of a planned skin flap. The objective was to induce collateralization and improve skin flap survival. Patterns of blood flow were tested by use of the base occlusion test. Flap survival of an acute control flap group was compared with that of the laser delay groups. RESULTS: Blood flowing to the distal flap area originated from the base of the flap area after laser delay. Flap survival of the laser delay groups was significantly improved over that of the control group. CONCLUSION: Both lasers were able to effectively induce collateralization and improve flap survival.